Relief-valve for internal-combustion engines.



H. L. WHITMAN. RELIEF VALVE FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED DEC. I5, 1913.

Patented July 4, 1916.

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HENRY I4. WHITMAN, OF ST. LOUIS, MISSOURI.

RELIEF-VALVE FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented July 4, 1916.

Application filedDecember 15, 1913. Serial No. 806,792.

To all whom itimag concern:

Be it known that I, HENRY L. WHITMAN, a citizen of the United States of America, and aresident of the city of St. Louis and State of Missouri, have invented certain new and useful Improvements in Relief- Valves for Internal-Combustion Engines, of which the following is a full, clear, and exact description, reference being had to the Y accompanying drawings, forming a part of this specification.

My invention relates to a relief valve for internal combustion engines, and has for its object the production of a relief valve adapted to be applied to the crank case of an internal combustion engine to relieve internal pressure in the crank case during the suction and power strokes of the engine; to prevent the escape of oil during these strokes, and to prevent entrance of dust and other material into the crank case during the exhaust and compression strokes of the engine.

Prior to this invention, crank cases of internal combustion engines have been provided with breather plates'for the purpose of permitting inward and outward flow of air to and from the engine crank cases during the operation of the pistons, and, while such plates offer resistance to the moving air currents, it has been found in practice that they do not effectually prevent oil from passing out of the crank case with the air. Neither do they prevent dust and other material from entering the crank case withthe inrushing air currents.

The preferred form of my invention comprises a valve housing having a passageway communicating with the crank case of an internal combustion engine, and a valve in said housing adapted to open in response to pressure from the crank case. During the exhaust and compression strokes of the engine, the valve closes the passageway leading to the crank case so that air cannot, en'- ter through said passageway. However, owing to the suction or partial vacuum in the crank case, a small quantity of air will, under ordinary conditions, leak through the bearings or other parts of the crank case,

and, during the power strokes, this small quantity of air is discharged through the valve housing.

The greatest utility of my relief valve lies in its application to a single cylinder four cycle engine, but it is'to be understood that the use of the invention is not limited to an engine of this kind.

Figure I is a side elevation partly in section illustrating an internal combustion engine equipped with my relief valve. Fig. II is a vertical section of the relief valve.

In the accompanying drawings: A designates an engine cylinder, 13 is the crank shaft, and C is the crank case.

D designates a tubular valve seat member having a threaded lower end and a valve seat .1 at its upper end. A closure 2 is hinged :to the upper portion of the valve seat member at 3, this closure being pro vided with perforations i.

5 designates a relief valve seated on the I valve seat 1 and having a stem 6 passing through the top wall of the closure 2. The valve stem is slidably fitted to the closure and the latter may be held in its closed position by a spring latch 7 secured-to the valve seat member.

The valve seat member is secured in a wall of the crank case so that its passageway 8 communicates with the interior of the crank case, and the upper end of said passageway is at certain times closed by the relief valve. During the exhaust and compression strokes of the engine piston asuction or partial vacuum is created in the crank case and the relief valve is then, firmly held on its seat so as to prevent the admission of air through the passageway 8. However, as previously stated, a small quantity of air will, under ordinary conditions, leak into the crank case at other points. During the suction and power strokes of the engine piston, the latter moves toward the crank case tending to compress the air therein, and the pressure is then relieved by the operation of the relief valve which opens automatically to relieve the crank case of internal pressure.

The object in hinging the closure 2 to the tubular valve seat member is to provide a closure that may be readily opened to permit the introduction of oil into the crank case, the oil being poured through the passageway 8. The valve 5 is secured to the closure 2 by a cotter pin 9 and in opening the closure thevalve is carried away from its seat to open the upper end of the passageway 8.

I claim 1. An internal combustion engine having a crank case, and means for preventing the admission of air to said crank case said crank case, said automatic relief valve de-.

vice being loose and free to open and close automatically during the operation of the engine to permit the escape of air through said tube in response to pressure in the crank case, said automatic relief valve device being a single valve arranged to permit a circulation of air through said tube in only one direction, and said tube being firmly closed at all points between said single valve and the crank case so that the circulation of air through the tube will be under the control of said single valve.

2. An internal combustion engine having a crank case, and means for preventing the admission of air to said crank case during the operation of the engine, said means in eluding a tube communicating With said crank case, a closure hinged to said tube and a single relief valve carried by said closure, said single relief valve being fitted to an end of the tube so as to permit a circulation of air through said tubein only one direction, said tube being firmly closed at all points between said single valve and the crank case so that'the circulation of air through the tube will be under'the control of said single valve and the said relief valve being loose and free to open and close automatically during the operation of the engine, so as to permit the escape of air through said tube in response to pressure in the crank case and to positively prevent the admission of air through said tube.

HENRY L. WHITMAN. In the presence of- E. B. LINN, E. CLARK.

Copies of this patent may be obtained for five cents each, by addressing the Commissioners! Patenta Washington, I). C. i V 

